The grim shroud of the COVID-19 pandemic ensures that 2020 will be considered an infamous year in the history of human disease.
But this dark chapter brought some surprises for which we can be grateful, too. In a new study, the researchers found that a 2020 outbreak of a mysterious paralyzing disease did not materialize on time – and in a strange way, we actually have to thank the coronavirus for that.
The condition in question is called acute flaccid myelitis (AFM). This polio-like neurological disease mainly affects children, causing muscle weakness and, in some cases, permanent paralysis and even death.
For decades, cases of AFM have been very rare, but in recent years, major outbreaks have occurred in the United States and elsewhere, apparently occurring every two years.
A previous body of research linked AFM to a rare virus called enterovirus D68 (EV-D68), and although it is not yet known how the virus manifests symptoms of AFM disease, coincident outbreaks in the pair have led researchers to think they are almost certainly related.
In the new research, a team led by Princeton University’s first author and infectious disease modeler Sang Woo Park tracked EV-D68 case patterns between 2014 and 2019, with the virus showing significant resurgences in even years – 2014, 2016, and 2018 – believed to be attributable to climate-based factors.
The data suggested that 2020 should have another success.
“We predicted that a major outbreak of EV-D68, and therefore an outbreak of AFM, would still have been possible in 2020 under normal epidemiological conditions,” explain the researchers in their study.
Of course, as the world suffered to testify, the epidemiological conditions of 2020 were anything but common, and the expected EV-D68 and AFM combo hit never came.
In the USA – a country with significantly more cases of COVID-19 than any other – the combined effects of physical detachment, quarantine and isolation policies and economic and civic outages appeared to not only slow the spread of SARS-CoV-2, but EV -D68 too.
“Our preliminary analysis indicates that the response to the COVID-19 pandemic likely affected the dynamics of an EV-D68 outbreak in 2020,” write the authors.
According to the researchers, there were 153 cases of AFM in 2016 and 238 cases in 2018, but only 31 cases in 2020.
In light of everything the United States has been through lately, these are some numbers to feel good about.
Still, there is no time for complacency – especially since the EV-D68’s unplanned gap year may have left a larger-than-normal void in viral immunity at the population level.
“Based on the low number of [predicted] In the EV-D68 cases in 2019, we would expect the number of susceptible individuals to increase, increasing the likelihood of a major outbreak, “said the team.
“If social detachment prevents the outbreak from occurring, the susceptible pool could increase even more.”
The findings are reported in Science, Translational Medicine.